Dawid Sadkowski, Weronika Baranowska, Kajetan Chalecki, Karolina Kuczkowska, Jan Rapczyński
Ornis Polonica 2026, 67: 110-124
https://doi.org/10.12657/ornis.2026.2.3
Abstract: The dynamically changing urban environment presents a significant challenge for many animal species, particularly predators such as owls. Their presence may serve as a bioindicator of environmental quality. The last comprehensive inventory of owls in Warsaw was conducted over three decades ago. The aim of this study was to assess the current abundance and species diversity of owls inhabiting the capital city of Warsaw in 2024. Field surveys were carried out using standard acoustic detection methods. Based on the urban landscape structure and the known ecological preferences of individual taxa,the inventory covered six owl species: the Tawny Owl Strix aluco, Long-eared Owl Asio otus, Little Owl Athene noctua, Pygmy Owl Glaucidium passerinum, Boreal Owl Aegolius funereus, and Barn Owl Tyto alba. A total of 107 Tawny Owl territories (2.1 terr./10 km2) and 15 Long-eared Owl territories (0.3 terr./10 km2) were recorded. In addition, a single Boreal Owl was observed, most likely representing an individual during spring migration. The results, when compared with historical data, indicate a relatively stable breeding population of Tawny Owls in Warsaw, a decline in Longeared Owl numbers, and the apparent complete withdrawal of the other studied species from the urban area. This inventory may serve as a reference point for future research and a methodological framework for conducting repeatable and comparable owl monitoring in urban environments.
Keywords: Asio otus, biodiversity in the city, city, owls, Strix aluco
